Update: The example I gave above is for a custom post type. There is no error in the case of a ‘page’. The Social Media Image simply doesn’t appear when loading the edit panel for a custom post.
In reference to these instructions:
“Show UI” must be “true”. If an existing top level page such as “tools.php” is indicated for second input, post type will be sub menu of that.
When I create a CPT using your plugin, it creates a top-level menu by default. But if I want to slot in a related CPT as a sub-menu, how do I know the name of the PHP file of the top-level item?
